Project Summary Oral ulceration is one of the most commonly encountered oral diseases, with an estimated prevalence of 4% in the USA. Managing large or multiple ulcers that are caused by diseases of unknown etiology, such as erosive lichen planus or aphthous ulcers which affect 25% of the population worldwide, is also a challenge to dentists and specialists. Ulceration of the oral mucosa can cause soreness that affects an individual's eating, drinking, and speaking; and ulcers of long-duration can even cause malnutrition that severely affects quality of life. Clinically, topical treatment with corticosteroids remains the first-line clinical therapy for oral ulcerations, and corticosteroids are delivered through a gel, oral base (paste) or rinse which provide temporary symptomatic relief. However, the effectiveness of current therapies is often greatly reduced by the fact that the medication can be diluted or eliminated within minutes by the patient's saliva, or through rubbing against the tongue or other parts of the mouth. Furthermore, continual usage of the amounts of the corticosteroid gel, paste, or rinse leads to potential systemic effects and significant local side effects, such as oral candidiasis, a yeast infection which further exacerbates the patient's soreness. In this grant application, we propose to develop a topical bioadhesive patch that will: 1) provide unidirectional and controlled drug release of corticosteroids; 2) provide a barrier to protect the ulcers from pain caused by friction; and 3) avoid side effects associated with current therapies. Specifically, we will develop a unique bioadhesive patch for the mucosal drug delivery in vitro and ex vivo. This new patch design will both control drug delivery and prevent drug leakage, thereby decreasing local side effects and increasing the therapeutic efficacy. Completion of the proposed Phase 1 research will result in the development of a targeted drug delivery product for localized release of corticosteroids to the mucosal surface for designated time. During the Phase 2 portion of the grant, we intend to focus on developing the patch/drug combination therapy into a product for preclinical trials based upon the results of our Phase 1 study. Thus the long-term goal of our research is to develop a bioadhesive patch into a clinical therapy that can be widely used to treat multiple or large oral ulcers with minimal side effects, thereby alleviating the debilitating effects of oral ulcerations and improving the quality of life for the patients.